PTL 1 discloses a “travel control device for an autonomous vehicle including an image input means for external world recognition, the travel control device for an autonomous vehicle that is characterized by including: an extraction means for extracting a traveling lane from an input image; a specifying means for specifying a lane through which the vehicle passes when the vehicle changes the lane from the traveling lane extracted by the extracting means; a calculation means for calculating an angle formed by the lane specified by the specifying means and a horizontal line; a detection means for detecting vehicle speed; and a control means for controlling steering based on the angle calculated by the calculation means and the vehicle speed detected by the detection means when there is a request for a lane change”.
According to PTL 1, it is possible to perform a steering angle control based on the angle formed by the traveling lane extracted by image processing and the horizontal line and the vehicle speed, and it is possible to smoothly and safely perform the lane change using autonomous travel control. Further, it is possible to perform the steering control based on any one reference line between two reference lines that partition the lane ahead of the vehicle extracted by the image processing, and thus, it is possible to continue the steering angle control based on the other reference line even when the reference line that is being used deviates from the input image in the middle of the steering angle control in the traveling lane during traveling or during the lane change. Thus, it is possible to more reliably, smoothly, and safely perform the autonomous travel control.